Loking Up: Admiring the Pleiades star cluster

Friday

Feb 26, 2010 at 12:01 AMFeb 26, 2010 at 12:48 PM

One of the most stunning sights in the heavens that you may enjoy without the benefit of a telescope is the Pleiades star cluster. This shining group of six +2nd magnitude stars are compacted close together and ride high in the winter sky as seen from mid-northern latitudes. Be sure not to miss the Pleiades if you have never noticed them before. They are a showpiece you will likely want to point out to your family and friends.

Peter Becker

One of the most stunning sights in the heavens that you may enjoy without the benefit of a telescope is the Pleiades star cluster. This shining group of six +2nd magnitude stars are compacted close together and ride high in the winter sky as seen from mid-northern latitudes.

Be sure not to miss the Pleiades if you have never noticed them before. They are a showpiece you will likely want to point out to your family and friends.

The next clear night in late February/early March, step out and look high in the south-southwest. Remember to let your eyes adapt to the darkness for a few minutes.

Here’s a way to locate the Pleiades: If you look about halfway up in the south, you find the constellation Orion, marked by the three “belt stars” in the middle of a large rectangle, cornered by four conspicuous stars. Once you find Orion, look to the upper right for a bright orange star (by the name of Aldebaran), at one end of a conspicuous “V” shape of stars, oriented on its side. Look again to the upper right of Aldebaran and you will come to the Pleiades cluster.

The Pleiades cluster is one of only a very few star clusters seen by unaided eyes, but there are hundreds of them you can find with binoculars or a small telescope across the sky. The Pleiades cluster is one of the closest to our solar system, 440 light years away.

The cluster has been recognized from antiquity. The Greeks referred to as the “Seven Sisters,” although only six stars are picked out by most people (without binoculars). There are hundreds of stars in the cluster, associated undoubtedly by their mutual admiration but definitely by gravitational attraction as they sail together in the depths of space.

Typical of an “open” star cluster, the Pleiades’ stars are bluish white, considered young on the astronomical scale of stellar development, and thus hotter than older, red or orange stars such as Aldebaran. You may have seen spectacular pictures of the Pleiades, its stars enveloped in haze and lit up blue. It takes a long-exposure photo to readily detect the haze; the cluster is passing through a thin nebula of dust, and the starlight is reflecting off the dust.

The six brightest stars are named Alcyone, Atlas, Electra, Maia, Merope and Taygeta. They are arranged like a ‘little dipper” but are not the Little Dipper that contains the North Star and is near the Big Dipper in the north.

Binoculars will give you a splendid and accentuated view, but the cluster is not as well appreciated with a higher magnification that comes with a telescope. This is because the cluster is so spread out, that you need a low magnification to fit them all in the field of view at once.

I mentioned the “V” shape of stars seemingly attached to the bright star Aldebaran. This “V” is actually another open star cluster and is known as the Hyades. Its stars are dimmer than the Pleiades’ and the cluster is not as compact. A survey of open star clusters, with a telescope and star map, will reveal how wonderfully diverse these cosmic groupings are. Many are very rich with stars and your imagination takes off as you note the wide variety of shapes the stars patterns within the clusters seem to take. Each is its own delight.

Aldebaran, the Hyades and the Pleiades are all within the constellation Taurus the Bull.

Full moon is on Feb. 28.

Keep looking up!

The writer may be contacted at pbecker@wayneindependent.com.

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